File-sharpening machine



1,560,312 E P. PITFIELD FILE SHARPENING MACHINE Filed Jan. 2, 1920 3 Sheets-Sheet 1 Nov. 3,1925.

Nov. 3, 1925.

E. P.l PlTFlELD FILE SHARPENING IACHINE Filed Jan. 2, 1920 3 Shoots-Sheet 2 l j AZ 02'/ y Q @ma Mm Nov. 3 1925. 1,560,312

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Patented 3, Y'19.25.

Y mi@ P. PITFIELD, 0F TAUNTON, MASSACHUSETTS.

APaialaiol-F ica. y

run-snaarnnme MACHINE.

' Application mea nume, mo. serial no. $48,810.

To all whom 'it may concern:

Be it known that I, EMLEN P. PITFIELD, a citizen of the United States, residing at Taunton, county lof Bristol, Commonwealth of l\Iassachusetts,'have invented certam new and useful Improvements in File-Sharpening Machines, of which the followlng 1s a specification.

This invention relates vto file sharpening machines and particularly to such a machine of the sand blast type.

The sharpening vof files by an abrasive blast has been'practiced with some success,

the method having been long accepted as correct in 4theory and if capable of perfected practice to be Aone 4in which the cutting qualities of a dull file are not only re-A stored but may lactually be improved.

To the end therefore of producing a machine capable of sharpening byabrasive blast without encountering the difficulties and objections usually incident thereto, I`

have devised my present invention.

The principal difficulties encountered in this kind of sharpening lie in the lack of uniformity 'of the blast, or in the amount, direction or period of application.` These difficulties may be analyzed under two heads; first, delivery of` the blast to the le, and second, feed of the ile past the blast. It will be obvious that unless the blast be properly directed against the cutting faces of the file, the sharpening effect may either be diminished or even lost altogether. It will furthermore b e seen that no matter'how accurately the lblast be delivered, unless the relative movement of the le past the blast is such as to give uniformity, the cutting action of the blast will lack uniformity and the ile will be left with an irregular surface, higher at some points and lower at others. Any such irregularity in the cutting plane of the file throws excessive wear on the most exposed teeth and renders useless the shorter teeth.

The primary object of my invention there fore isto provide a machlne in which files may be sharpened rapidly and with complete uniformity. In devising such a machine I have furthermore made various improvements in structure and arrangement of parts, by which the machine as a whole is perfected and simplified and rendered economical in operation.

In the form shown in the accompanying drawings my invention is embodied 1n a manner well adapted to ractical use and the features thereof wel illustrated. In the drawings: l Fig. I is a side elevation of a machine 1n accordance with my invention.

II a plan view thereof. l

Flg. III aA sectional detail of the blast nozzle. l

Flg. IV a similar view showing nozzle ad'ustment.

. ig. V a sectional view showing the nozzle arrangement from-the rear.

t Fllg. VI a detail plan ofthe cam lcont. Fig. VII a similar view illustrating opera ion.

Fig. VIII .a sectional view of the cam the caxn frame consisting of a pair of legged trusses n 1 and 2, crossed braced as at.3. The members 1 and 2 carry at the sides oftheir tops, lguideways 11 and 12, respectively, through which passes the longitudinal hars f1 on which is mounted ythe file carrier.

Above the supporting frame and mounted thereon is a casing 6 which as shown in Fig. I is inclined downwardly towards a reservoir 7 in which Aa pump 8 operatesco drive a sand blast upwardly through the feed pipe 9. At the lower end of the casing 6 and above the reservoir 7 are the guns 20 and 21 for the delivery of the abrasive blast to the file surfaces. These uns are adjustably mounted in a base 22.

he base 22 is provided with a pair of guide caps 23 channeled at 24 to receive the annular flange 25 formed on the base 22.

The caps 23 are threaded onk the ,Iends of the l feed ipes 26 and 27, these two pipes being a justed by a stem 28 turned by a milled head 29. The stem 28 is hollow and perforated as at 281 thus permitting an equalizing of the pressures behind the guns 20 and 21. From the pipes 26 and 27 the connecting pipes 30 and 31 run toNcouplmg members 32 and 33 in which the guns 20 and 21 are set. The cou lings 32 and 33 are swiveled on a T-mem er 34.which connects with the pipe 9 through an elbow 91. The connecting elbows 35 and 36 which join the T-head 34 with the coupling 32 are tapped to receive adjusting plugs 37 having squared wrench heads 371. his permits an adjustment adjacent the gun itself of the feed of the blas The pump 8 has a shaft 81 which is belted at 40 to a pulley 41 on the shaft 42. The drivin pul e 43 has a clutch engagement with t e pu e 4l and through it drives the shaft 42. his shaft carries an elliptical gear 44 meshing with a second ellipt1cal gear 45 on a shaft 46. On this shaft is al crank arm 47 slotted at 48. A itman 49 is adjustably connected through t e slot 48 and connects b the rods 4 whlch by this means it reciprocates in their guideways.

In adjustin the effective throw of Ithe crank 47 on t e pitman 49, the position of the slide is maintained and assured by a pair of ears 53 which pass a stud 51 on the luard 52. These ears and the stud are so disposed that they embrace when the pitman 49 is in horizontal alinement with the crank 47 in which position any resetting of the effective crank length is made. When in this position it isimpossible for the slide to be moved so that the throw of the crank m'ay be adjusted at any time without danger of displacing the slide relative to the guns 20 and 21. In this way, the machine may be quickly and accurately adjusted for any length of file without the possibility of having the file clamps overrun the guns or losin the correct position of the base of the e.

Mounted on the rods 4 at the forward end of the machine is the le carrier. This consists of a head having a pair of transverse guides 61 on which is slidably mounted a yoke 62. The yoke 62 has a movement back and forth laterally of the head 60, this movement`being imparted to it by a heartshaped cam groove 63, formed in a ratchet disc 64. The yoke 62 is provided with a roller stud 65 which travels inthe heartshaped cam groove 63, thus imparting to the yoke 62 its horizontal traverse as the disc 64 is rotated.

The rotation of the disc 64 is effected in a step by step movement bythe engagement of a pawl 66 with the ratchet teeth 67 of the disc. The pawl 66 is mounted on an arm 68 a clamped cross head 50 to betweeny a pair of collars 72 'on the rod 73.

This rod 73 lies on the opposite side of the machine as viewed in Fig. I, being connected at one end to the cross head 50 and running the principal part of its length substantially parallel with the adjacent slide rod 4 finds its bearing in a bracket 74 depending from the lower part' of the head 60. The end of the rod 73 is headed as at 75 and between the head and bracket 74 is interposed a spring 76. A stop 77 is set in suitable position on thev rod 73 so that it will abut the face of the bearing 11 at the proper moment in the travel of the bars 4 to work pawl arm 68. This movement of the pawl arm movin the cam disc 64 sets the file over one notc to bring the-blast of the guns on another parallel path along the e. The set over takes place just as lthe guns have cleared the end ofthe file so that there is no dwell in the action of the guns on the file which would givel irregularity in the abrasion of the file surface. It will be noted that this lateral motion is accomplished at the end of the backward movement of the le carrying head during the return stroke of the carriage. The stop' 77 in encountering the face of the bearing 11 compresses the spring 76. At the moment of return therefore, the spring 76 is under compression so that while the stop 77 is held against the face of the bearing 11 the spring 76 takes up the returning movement of the head 60, causing a movement of vthe lever 71 which is carried by the head and thus withdrawing the pawl 66 one tooth in the ratchet 67. i

The traverse of the frame 62 is imparted to a pair of lever arms 78. These arms are llo fast on vertical shafts 79 which also carry.

correspondingly disposed shortl arms S0. Pivoted on the arms 80 is the file carrier bar 81. havin at its forward end a le clamp 90 injw ich the file F is held.

The le clamp. 90 is preferably made detachable having a short shank 91 adapted to fit within the socketedl end of the bar 81. and be held by the set screw 82. The clamp has an upper movable jaw 92 preferably slightly shorter than the lower jaw frame member 90 and is adjusted by a screw 93 so as to clamp the shank of the file F.

In' operation the machine is s'et according to the size and nature of the file to be sharpj ened and the connection between the pitman 49 and the crank arm 47 'being adjusted to give the proper throw. The guns 20 and 21 are set at the desired angle so as to direct the blast against thefile surface in desired direction. Power being applied to the loose pulley 43, the machine is started by a movement of the lever 94 extending transversely of the front legs 1 of themachine. This rocks similar lever 95 at the opposite side of the machine and through the connecting.r rod 96 and a. cam shift 97 throws the pulley 93 so that the clutches 98 engage and drive the shaft 46, thus operating the machine.

Various modifications may be made in the parts of the machine and in the assembly thereof and equivalent mechanisms may be substituted for many of its elements, all such however being within my invention if within the limits of the appended claims.

What I therefore claim and desire to secure by Letters Patent is:

l. In a ile sharpening machine, means for delivering an abrasive blast, a file carrier movable longitudinally thereto, and means for moving said carrier at a constant speed including a crank, and a pair of elliptical gears operatively connected in compensating relation to said crank.

2. In a file sharpening machine, means for delivering an abrasive blast, a file carrier movable longitudinally and laterally thereto, a cam for moving said file carrier v laterally, a protective housinnr for said cam adapted to protect the cam from the accumulation of abrasive from the abrasive delivery, and means for moving said carrier longitudinally at a constant speed including a crank, and a pair of elliptical gears operatively connected in compensating relation to said crank.

3. In a file sharpening machine, a pair of angularly adjustable abrasive blast delivery nozzles, means for supplying steam thereto, a blast intake intermediate the ends of said nozzles and constructed to follow the ad just-ments thereof, and a pressure equalizing connection comprising a pair of oppositely disposed feed pipes between the rear ends of said nozzles and a hollow erforated stem for relatively adjusting sai pipes to take up the an ular adjustment of said nozzles.

.4. In a igile sharpening machine, a pair of angularly adjustable abrasive blast delivery nozzles, means for supplying steam thereto, means for supplying sand to said nozzles, said steam and sand supplying means connected with sand nozzles to follow the adjustments thereof, an abrasive reservoir, a

pump in said reservoir delivering to said' nozzles, a tile carrier movable longitudinally and laterally relative to said nozzles, a cam for moving said le vcarrier laterally, a housing adapted to protect said cam against accumulation of abrasive thereon, and means for driving said file carrier lon itudinally including a crank and `a pair ogfy elliptical gears operatively connected in compensating relation to said crank.

5. In a file sharpening machine a pair of pump in said reservoir and operativelyI piped to said guns intermediate their ends, and a iuid pressure supply connected tosaid guns behind the abrasive connection therein,`

saidl abrasive blast guns being intercommunicating at their air intake ends.

7. In a le sharpening machine a pair of blast guns swivelled intermediate their ends, an abrasive reservoir, and connected with said guns through their swivel mounts, a fluid pressure supply piped to said guns behind the abrasive connection therein.

8. In a file sharpening machine, a pair of blast guns swivelled intermediate their ends, an abrasive reservoir connected with said guns through their swivel mounts, a fluid pressure supply piped to said guns behind the abrasive connection therein, and an adjustable air connection between said guns at their air intake ends.

9. In a iile sharpening machine, means for delivering an abrasive blast, a file carrier, means .for moving said file carrier laterally relative to said delivery, comprising a ratchet, a cam carried by said ratchet and operatively connected with said le carrier, a pawl adapted to intermittently rotate said ratchet, and means for actuating said pawl.

10. In a file sharpening machine, means for delivering an abrasive blast, a file carrier, means for moving said file carrier laterally relative to said delivery, comprising a ratchet, a cam carried b said ratchet'and operatively connected wit -said file carrier, a pawl adapted to intermittently rotate said ratchet, a spindle for said pawl, an operating arm on said spindle, an operating rod for said arm, and means for reciprocating said rod.

11. In av file sharpening machine, the combination with an abrasive reservoir and a blast gun, of a pump having draft upon said reservoir and connected with said gun.

12. In a file sharpening machine, the combination with an abrasive reservoir and a blast gun, of a rotary pump having draft upon said reservoir and connected with said gun.

13. In va file sharpeningmachine, a pair of blast guns swiveled between their ends, an abrasive reservoir, and a pump having draft upon said reservoir and connected with said guns through their swivel mounts.

14. In a file sharpening machine, a pair of blast guns swiveled between their ends, an abrasive reservoir, and a pump havin draft upon said reservoir and connecte with said uns through their swivel mounts and a Hui pressure supply piped to said guns behind the abrasive connection therein.

15. In a file sharpening machine,the combination with a longitudinally movable carriage of a laterally movable file' carrier mounted on said carriage, a heart shaped cam for moving said file carrier laterally, a casing enclosing said cam and means including a connecting rod movable with said 10 carriage and operatmg'4I said cam.

In testimony wherecf- I aix my signature. y EMLEN P.l PITFIELD. 

